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Head-to-head comparison

GPT-5.6 Terra vs. Gemini 3.8 Flash

Compare published benchmark results from matching versions and cohorts, API pricing, and technical specifications. Any documented test setup differences remain visible.

shared result series
23
distinct benchmarks
23
latest retrieval
2026-09-02

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Specifications

General specifications

Release date, availability, context window, architecture, and published parameter counts at a glance. Undisclosed details remain marked as unavailable.

Specifications for GPT-5.6 Terra and Gemini 3.8 Flash
AttributeGPT-5.6 TerraGemini 3.8 Flash
ProviderOpenAIGoogle
ReleasedJun 26, 2026Sep 2, 2026
AvailabilityActiveActive
Model typeProprietaryProprietary
ParametersNot publishedNot published
ArchitectureNot publishedNot published
Context window1,050,000 tokens1,048,576 tokens
Knowledge cutoffFebruary 16, 2026March 2026
Technical sourcesModel, Context, Knowledge cutoffModel, Knowledge cutoff

Pricing

API pricing compared

The table compares official standard API rates per 1M tokens, including published cache pricing. Batch, fast, priority, regional surcharges, tool calls, and cloud platform pricing are excluded.

API pricing for GPT-5.6 Terra and Gemini 3.8 Flash
Price typeGPT-5.6 TerraGemini 3.8 Flash
API input$2 ≤272K / $4 >272K$0.75
API output$12 ≤272K / $18 >272K$3.75
Cache read$0.2 ≤272K / $0.4 >272K$0.07
Cache write (5 min.)$2.5 ≤272K / $5 >272KNot listed
Cache write (1 hr.)Not listedNot listed
Price verified08/11/2026 Source09/02/2026 Source
GPT-5.6 TerraGemini 3.8 Flash
API inputUSD per 1M tokens, base tier
GPT-5.6 Terra$2
Gemini 3.8 FlashLower price$0.75
API outputUSD per 1M tokens, base tier
GPT-5.6 Terra$12
Gemini 3.8 FlashLower price$3.75
Cache readUSD per 1M tokens, base tier
GPT-5.6 Terra$0.2
Gemini 3.8 FlashLower price$0.075

Key to the marks:better valuebetter, but not conclusivetie

Pricing by provider

Direct developer pricing and provider endpoint tariffs routed through OpenRouter are listed separately. Prices are in USD per 1M tokens. Context-dependent direct tiers plus regional, Flex, Priority, and other OpenRouter tariffs remain individually identifiable.

Provider pricing for GPT-5.6 Terra and Gemini 3.8 Flash
ModelProviderPurchase route and tariffInput per 1M tokensOutput per 1M tokensSource
GPT-5.6 TerraOpenAIDirect from developerUp to 272,000 context tokens$2$12Source08/11/2026
OpenAIDirect from developerAbove 272,000 context tokens$4$18Source08/11/2026
Amazon BedrockVia OpenRouteramazon-bedrock/us-east-1$2.2$13.2Source09/02/2026
AzureVia OpenRouterazure$2$12Source09/02/2026
AzureVia OpenRouterazure/eu$2.2$13.2Source09/02/2026
AzureVia OpenRouterazure/us$2.2$13.2Source09/02/2026
OpenAIVia OpenRouteropenai$2$12Source09/02/2026
OpenAIVia OpenRouteropenai/fast$4$24Source09/02/2026
OpenAIVia OpenRouteropenai/flexLowest listed price: $1Lowest listed price: $6Source09/02/2026
Gemini 3.8 FlashGoogleDirect from developerStandard API$0.75$3.75Source09/02/2026
GoogleVia OpenRoutergoogle-vertex/global$0.75$3.75Source09/02/2026
GoogleVia OpenRoutergoogle-vertex/global/flexLowest listed price: $0.375Lowest listed price: $1.875Source09/02/2026
GoogleVia OpenRoutergoogle-vertex/global/priority$1.35$6.75Source09/02/2026
Google AI StudioVia OpenRoutergoogle-ai-studio$0.75$3.75Source09/02/2026
Google AI StudioVia OpenRoutergoogle-ai-studio/flexLowest listed price: $0.375Lowest listed price: $1.875Source09/02/2026
Google AI StudioVia OpenRoutergoogle-ai-studio/priority$1.35$6.75Source09/02/2026

Performance

Shared benchmarks

Only published results with the same benchmark version, task, metric, and comparison cohort are paired. Different reasoning levels, agents, harnesses, or output limits appear directly in the table.

Capability profile from matched benchmarks

Each axis averages directly matched benchmark families. A value of 100 means the stronger value within this pair, not a universal quality score.

255075100CodingReasoningMathematicsKnowledgeFinanceLegalAgentic tasksMultimodal
GPT-5.6 Terra
Gemini 3.8 Flash
Coding: 88.2 / 92.1 (5 benchmark families)
Reasoning: 96.3 / 100 (1 benchmark family)
Mathematics: 100 / 64.9 (1 benchmark family)
Knowledge: 96.1 / 100 (1 benchmark family)
Finance: 95.1 / 98.7 (4 benchmark families)
Legal: 68.7 / 98.1 (3 benchmark families)
Agentic tasks: 97.7 / 99.2 (2 benchmark families)
Multimodal: 97.1 / 100 (1 benchmark family)

23 matched rows from 23 benchmark families were considered. The radar shows 8 of 12 comparable categories.

GPT-5.6 TerraGemini 3.8 Flash
Code MigrationOverall. Higher is better. No documented setup difference
GPT-5.6 TerraWinner47.804 %
Gemini 3.8 Flash36.546 %
EMBOverall. Higher is better. No documented setup difference
GPT-5.6 Terra66.205 %
Gemini 3.8 FlashWinner72.196 %
Finance Agent (v2)Overall. Higher is better. No documented setup difference
GPT-5.6 Terra54.436 %
Gemini 3.8 FlashWinner61.435 %
GPQA DiamondOverall. Higher is better. No documented setup difference
GPT-5.6 Terra90.909 %
Gemini 3.8 FlashWinner94.444 %
Harvey's Legal Agent BenchmarkOverall · Task fully resolved. Higher is better. No documented setup difference
GPT-5.6 Terra0.833 %
Gemini 3.8 FlashWinner10 %
Legal Research BenchOverall · All-pass. Higher is better. No documented setup difference
GPT-5.6 TerraWinner41.346 %
Gemini 3.8 Flash38.942 %
LegalBenchOverall. Higher is better. No documented setup difference
GPT-5.6 Terra85.105 %
Gemini 3.8 FlashWinner86.993 %
LiveCodeBench v6Overall. Higher is better. No documented setup difference
GPT-5.6 Terra85.93 %
Gemini 3.8 FlashWinner89.484 %
MedCodeOverall. Higher is better. No documented setup difference
GPT-5.6 Terra43.414 %
Gemini 3.8 FlashWinner48.135 %
MedScribeOverall. Higher is better. No documented setup difference
GPT-5.6 Terra82.869 %
Gemini 3.8 FlashWinner84.496 %
MMLU-ProOverall. Higher is better. No documented setup difference
GPT-5.6 Terra86.659 %
Gemini 3.8 FlashWinner90.221 %
MMMU-ProOverall. Higher is better. No documented setup difference
GPT-5.6 Terra86.474 %
Gemini 3.8 FlashWinner89.075 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for GPT-5.6 Terra and Gemini 3.8 Flash
Benchmark and taskGPT-5.6 TerraGemini 3.8 FlashSource
Code MigrationOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner47.804 %
36.546 %
Vals AI
Source details
Data as of: 09/01/2026
EMBOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
66.205 %
Winner72.196 %
Vals AI
Source details
Data as of: 09/01/2026
Finance Agent (v2)Overall
Test details
No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better
54.436 %
Winner61.435 %
Vals AI
Source details
Data as of: 09/01/2026
GPQA DiamondOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
90.909 %
Winner94.444 %
Vals AI
Source details
Data as of: 09/01/2026
Harvey's Legal Agent BenchmarkOverall · Task fully resolved
Test details
No documented difference in the test setupVersion: 1Metric: task resolution rateScoring: Higher is better
0.833 %
Winner10 %
Vals AI
Source details
Data as of: 09/01/2026
Legal Research BenchOverall · All-pass
Test details
No documented difference in the test setupVersion: 1Metric: all-pass rateScoring: Higher is better
Winner41.346 %
38.942 %
Vals AI
Source details
Data as of: 09/01/2026
LegalBenchOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
85.105 %
Winner86.993 %
Vals AI
Source details
Data as of: 09/01/2026
LiveCodeBench v6Overall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
85.93 %
Winner89.484 %
Vals AI
Source details
Data as of: 09/01/2026
MedCodeOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
43.414 %
Winner48.135 %
Vals AI
Source details
Data as of: 09/01/2026
MedScribeOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
82.869 %
Winner84.496 %
Vals AI
Source details
Data as of: 09/01/2026
MMLU-ProOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
86.659 %
Winner90.221 %
Vals AI
Source details
Data as of: 09/01/2026
MMMU-ProOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
86.474 %
Winner89.075 %
Vals AI
Source details
Data as of: 09/01/2026
MortgageTaxOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner67.329 %
65.342 %
Vals AI
Source details
Data as of: 09/01/2026
ProgramBenchOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
0.5 %
Winner1 %
Vals AI
Source details
Data as of: 09/01/2026
ProofBenchOverall
Test details
No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is better
Winner74 %
48 %
Vals AI
Source details
Data as of: 09/01/2026
Public Benefits Bench v1.1Overall
Test details
No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is better
62.382 %
Winner65.291 %
Vals AI
Source details
Data as of: 09/01/2026
SAGEOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner47.003 %
35.064 %
Vals AI
Source details
Data as of: 09/01/2026
SkillsBenchOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is betterSettings: Harness: OpenHands
Winner58.895 %
57.985 %
Vals AI
Source details
Data as of: 09/01/2026
SWE-bench VerifiedOverall
Test details
No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better
Winner95.4 %
80 %
Vals AI
Source details
Data as of: 09/01/2026
TaxEval v2Overall
Test details
No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better
Winner76.166 %
74.448 %
Vals AI
Source details
Data as of: 09/01/2026
Terminal-Bench 2.1Overall
Test details
No documented difference in the test setupVersion: 2.1Metric: accuracyScoring: Higher is better
77.528 %
Winner81.273 %
Vals AI
Source details
Data as of: 09/01/2026
Vals IndexOverall
Test details
No documented difference in the test setupVersion: 2Metric: weighted index scoreScoring: Higher is better
59.588 %
Winner62.252 %
Vals AI
Source details
Data as of: 09/01/2026
Vibe Code Bench v1.1Overall
Test details
No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is betterSettings: Harness: OpenHands
74.594 %
Winner78.651 %
Vals AI
Source details
Data as of: 09/01/2026

Key to the marks:better valuebetter, but not conclusivetie

How to read this comparison

Winning one benchmark is not an overall verdict

Your workload, budget, and required context length matter most. A coding benchmark says little about visual understanding or agent performance.

The standard price table uses direct developer rates. The provider comparison labels OpenRouter endpoints, regions, and special tariffs separately.

Every result links to its measurement source and retrieval date. Labels distinguish vendor reports, official benchmark leaderboards, and independent evaluations. Disputed or archived results are excluded.

More matchups

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View the complete LLM comparison